Synthesis of 3-Unsubstituted Phthalides from Aryl Amides and Paraformaldehyde via Ruthenium(II)-Catalyzed C–H Activation.

A straightforward and convenient route has been developed for the synthesis of 3-unsubstituted phthalide derivatives from aryl amides and paraformaldehyde by ruthenium(II)-catalyzed C–H activation. The reaction proceeds through tandem ortho-hydroxymethylation of aryl amide and subsequent intramolecular lactonization. [ABSTRACT FROM AUTHOR]